Hello fellow F4i owners. This is my first post on this forum. I recently purchased a 2006 F4i. Its my third street legal bike and my first real street bike. I’ve owned multiple BMW’s and finally sold them and bought an F4i. I have to say I love it. However. I quickly found that it just wasn’t quite enough so I saved some cash and decided to do some upgrades. The bike came used with 7k on it, a Scorpion exhaust and some after market taillights and front turn signals. I went with a Power Commander III USB, a fresh Dyno tune, new fork springs because I’m a larger dude and new sprocket and chain down 1 up 1. Also threw some fresh Michelin Pilot Powers (single compound) The bike feels great now. Almost like riding a completely different bike. Here my issue. After the dyno the technician showed me the print out. According to them my bike (after all the upgrades and dyno) is making 93hp at 1300rpms and a max torque of 42. I know the torque is much improved now. But the HP seems low. I thought the F4i was over 100hp stock. Does anyone else feel like my HP is low?? This bike is super clean and was babied by the previous owner. So I don’t think its just loss from engine wear. Any ideas? Thanks

 

Expect to be in the ballpark of 95 hp. Add ons don't do much for the f4i without internal engine work. I only gained 0.4 hp after a dyno tune but the bike runs so much better after and smoother too. Lots of factors affect your dyno tune like temp, humidity, how far above sea level u are...... Mine with 25k miles put down 97.4 hp after my tune but like I said, the power delivery is so much better all around. Did u do the PAIR mod before your tune? That will yield better air fuel readings while tuning.

 

I did not do a PAIR mod to bike before the tune. I’ve spent to much already. Perhaps that could happen farther down the road. I wasn’t really expecting a big HP jump. I just assumed that the bike had more stock HP than it really does.

 

Rear wheel HP from dyno test is always less than figures that people claim they have.
For a street bike, 93 HP seems plenty, have you considered becoming a better rider rather than sinking more money into the bike?

Without suspension mods, likely HP increasing mods are just going to waste when you're really pushing the limits; but on public streets, for street bike, 93 HP is plenty for someone with decent riding skills.

Hone your riding skill with a few track days, get suspensions sorted out to suit you, both of which will allow you to use the existing 93 HP to the max. If that's still not enough, get a different bike, F4i's are more practice steeds than racing breeds.

 

I’m not saying 95hp isn’t enough. All I was asking is if it seemed lower than it should be. I was just trying to make sure the place that did the dyno didn’t mess anything up. I go to track days twice a month since I bought the f4i last summer. I have been honing my skills on the track since then. Thanks for the advice though.

 

do you have your print outs? my bike is producing max power at 12,500 and max torque at 10,200

 

On my print out I got 103.22HP at 10k rpm and 45.57 torque at 13k rpm

 

actually my bike w/ 21k miles (a 2001) produced virtually the same w/ a zero mapped ecu. 93.81whp and 41.73tq.

I'm running a different model ECU so.. I can't have an auto-tune (nor do I want to). Right now I'd datalogging all info and slowly tuning everything to 13.2 to 12.8 AFR at least at the upper Throttle positions. At lower positions I'm moving to around the 14.0 mark or so for fuel economy purposes.

Even running a 0 map.. WOT is damn close to 12.8 - 13.2 or so. At WOT the leanest I'll go is about 12.3 or so, the richest is about 13.4. Typically it runs leans vs. rich in almost all spots.. (at least w/ your basic bolt ons).

What you can increase though is your ridability feeling though. Why... because when you're not at WOT.. the A/F ratios are weird. For example at 10% throttle near 3k- 4500 rpms.. I'm running an A/F ratio of 16+ ??

So why the datalogging and wideband equipment.. because to tune the bike is $0. To return w/ additional mods is again $0. If I get a new bike.. I take all my stuff w/ me. Power to be gained is minimal w/o major mods. One of the most important probably being a full exhaust.

Everyone always searching for the most HP.. but seriously how many times are these people out on the track in the first place. Oh well just my two cents.. if anyone has any tips on A/F tuning please shoot them my way. A decently priced aftermarket header would be really nice too..

 

I do have a single print out. It doesn’t tell you much other than what I said in my original post.

 

The machines new made 109hp (via wikipedia) at the crank which is about 90 - 95 at the wheel max depending on who you talk to and how you figure it. Fuel and engine oil used, ambient air temp, barometer, humidity, dyno setup, tire condition (wheelspin) are some things that cause differences in dyno readings. Generally speaking, the f4i will produce about 95 at the rear wheel in good condition stock on a good day.